Atomic Models and Lithium Atom

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Questions and Answers

What happens to a metal atom when it transfers its electrons to a nonmetal atom?

It becomes a neutral atom.

It becomes a positive ion (cation). (correct)

It remains unchanged.

It forms a metallic bond.

Which prefix is used to denote three atoms in a molecular compound?

Penta-

Di-

Tri- (correct)

Tetra-

What characteristic do ionic compounds typically exhibit at room temperature?

They form a solid and are brittle. (correct)

They are usually gaseous.

They are soft and flexible.

They are liquid and conductive.

How do ionic compounds behave when heated or dissolved in water?

They can carry electricity. Signup and view all the answers

In the chemical formula CO, what can be inferred about the carbon atom?

It has one atom present, but 'mono-' is not used. Signup and view all the answers

Which of the following is a physical change?

Dissolving salt in water Signup and view all the answers

Which sign indicates a chemical change?

New color appears Signup and view all the answers

What is the maximum number of electrons in the third energy level of an atom?

8 Signup and view all the answers

What characteristic is associated with physical changes?

Reversibility of the change Signup and view all the answers

In the Bohr model, what must be noted about filling energy levels?

You must fill each level completely before moving to the next Signup and view all the answers

Which statement best describes ionic compounds using the analogy provided?

Metal atoms donate electrons like shy boys disinterested in keeping them. Signup and view all the answers

Which of the following changes cannot usually be reversed?

Burning wood Signup and view all the answers

What are valence electrons important for in an atom?

Predicting chemical reactivity Signup and view all the answers

What did Dalton propose about the structure of atoms?

Atoms are like tiny, indivisible balls. Signup and view all the answers

What significant discovery did Thomson make about atoms?

Atoms contain electrons, which are negatively charged. Signup and view all the answers

According to Rutherford's model, what is primarily found in an atom?

Mostly empty space with a small nucleus. Signup and view all the answers

In Bohr's model of the atom, how do electrons behave?

They orbit the nucleus in specific paths. Signup and view all the answers

What determines the atomic number of an element?

The number of protons in the nucleus. Signup and view all the answers

What charge does a lithium ion carry after losing an electron?

2+ charge Signup and view all the answers

What does a WHMIS symbol of a gas cylinder represent?

A gas under pressure. Signup and view all the answers

Which of the following best describes matter?

Anything with mass that takes up space. Signup and view all the answers

Which of the following is an example of an intensive physical property?

Boiling point Signup and view all the answers

What defines chemical properties?

Required an alteration of the substance to be known Signup and view all the answers

Which of the following statements is true regarding extensive properties?

They depend on the amount of substance present. Signup and view all the answers

Which of these properties requires a change in the substance to be measured?

Reactivity Signup and view all the answers

Which property is a characteristic of a solid substance?

Definite shape Signup and view all the answers

What is one way to classify matter based on its composition?

Element, compound, or mixture Signup and view all the answers

Which of the following is an example of an extensive physical property?

Weight Signup and view all the answers

Which of the following best describes malleability?

Ability to be flattened into sheets Signup and view all the answers

Study Notes

Dalton’s Model

Atoms are tiny, solid, indivisible balls
Atoms combine in whole number amounts

Thomson’s Model

Atoms contain tiny, negatively charged particles called electrons
Atoms are positively charged with electrons stuck inside

Rutherford’s Model

Most of an atom is empty space
The center has a small, dense core (nucleus) with a positive charge
Electrons move around the nucleus

Bohr’s Model

Electrons orbit the nucleus in certain paths or energy levels

Lithium Atom

Protons: positively charged particles in the nucleus
Neutrons: neutral particles in the nucleus
Electrons: negatively charged particles orbiting the nucleus

Atomic Number and Mass

The atomic number equals the number of protons in an atom
The number of electrons equals the number of protons
The total particles in the nucleus equal the atomic mass rounded off
The number of neutrons equals the total particles minus the protons

Ion Charge of a Lithium Ion

A lithium ion loses an electron
Charge: 3 positive protons – 1 negative electron = 2+ charge

Reactions and Charges

Alkali metals give 1 electron, so their ion charge is 1+
Alkaline earth metals give 2 electrons, so their ion charge is 2+
Halogens gain 1 electron, so their ion charge is 1-
Noble gases don’t react, and their charge is 0

WHMIS

Workplace Hazardous Materials Information System
Warns about dangers of materials

MSDS

Material Safety Data Sheet

Physical Properties of Matter

Matter is anything that has mass and takes up space
Physical properties describe what matter looks like or how it behaves without changing its chemical structure

Examples of Physical Properties

Appearance
- Color, texture, luster
State
- Solid, liquid, gas
Boiling and freezing points
Density
Malleability
Ductility

Types of Properties

Intensive properties don’t depend on the amount
Extensive properties depend on the amount

Chemical Properties

Can only be found by changing a substance into something else

Physical Changes

Change in the shape, size, or form of a substance, but it stays the same substance
Examples:
- Water turning into ice
- Dissolving salt in water
- Breaking a rock
- Tearing a piece of paper

Chemical Changes

A substance reacts and forms a completely new substance
Examples:
- Baking bread
- Fireworks exploding
- Burning wood
- Cooking an egg

How to Tell the Difference Between Physical and Chemical Changes

Physical changes are often reversible
Chemical changes are usually irreversible

Bohr Models

Used to predict reactivity in elements

Valence Electrons

Valence electrons are electrons on the last energy level

Drawing Bohr Models

Draw nucleus
Write number of neutrons and protons
Draw energy levels
Draw electrons in energy levels

Rules for Energy Levels

Level 1 can hold a maximum of 2 electrons
Level 2 can hold a maximum of 8 electrons
Level 3 can hold a maximum of 8 electrons
Level 4 can hold a maximum of 32 electrons
Fill one level before going onto the next

Ionic Compounds

Metal atoms want to give away electrons
Nonmetal atoms want to take electrons
Metal and nonmetal atoms trade electrons
Metal atom becomes a positive ion
Nonmetal atom becomes a negative ion
Ions stick together and form a solid at room temperature
Brittle and break easily
Conductors of electricity when heated or dissolved in water

Prefixes for Number of Atoms

Mono: 1
Di: 2
Tri: 3
Tetra: 4
Penta: 5
Hexa: 6
Hepta: 7
Octa: 8
Nona: 9
Deca: 10

Example

Diphosphorus pentoxide
- Two phosphorus atoms
- Five oxygen atoms
- Chemical formula: P₂O₅

Writing Formulas for Molecular Compounds

Not expected to write formulas for the state of the compound at room temperature

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Description

Explore the different atomic models proposed by Dalton, Thomson, Rutherford, and Bohr in this quiz. Test your knowledge on the structure of a lithium atom, including protons, neutrons, and electrons, as well as how atomic number and mass are calculated. Perfect for high school chemistry students!